Package com.linkedin.venice.router.api.routing.helix

Class HelixGroupLeastLoadedStrategy

java.lang.Object

com.linkedin.venice.router.api.routing.helix.HelixGroupLeastLoadedStrategy

All Implemented Interfaces:

HelixGroupSelectionStrategy

public class HelixGroupLeastLoadedStrategy
extends Object
implements HelixGroupSelectionStrategy

This strategy is tried to distribute more load to Helix Groups with more capacity. Since the qps to a specific Router is not that high, so it is acceptable to use synchronized method here. TODO: if we notice a performance issue with the synchronized implementation, we could tune it better to use Atomic data structures by sacrificing the accuracy. This class is also leveraging TimeoutProcessor to handle potential group counter leaking issue.

Field Summary

Fields

Modifier and Type	Field	Description
static final int	MAX_ALLOWED_GROUP

Constructor Summary

Constructors

Constructor	Description
HelixGroupLeastLoadedStrategy(TimeoutProcessor timeoutProcessor, long timeoutInMS, HelixGroupStats helixGroupStats)

Method Summary

Modifier and Type	Method	Description
void	finishRequest(long requestId, int groupId, double latency)	Notify the corresponding Helix Group that the request is completed, and the implementation will decide whether any cleanup is required or not.
int	selectGroup(long requestId, int groupCount)	Select a Helix Group for the current request.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

MAX_ALLOWED_GROUP

public static final int MAX_ALLOWED_GROUP

See Also:

• Constant Field Values

Constructor Details

HelixGroupLeastLoadedStrategy

public HelixGroupLeastLoadedStrategy(TimeoutProcessor timeoutProcessor,
 long timeoutInMS,
 HelixGroupStats helixGroupStats)

Method Details

selectGroup

public int selectGroup(long requestId,
 int groupCount)

Description copied from interface: HelixGroupSelectionStrategy

Select a Helix Group for the current request.

Specified by:

selectGroup in interface HelixGroupSelectionStrategy

finishRequest

public void finishRequest(long requestId,
 int groupId,
 double latency)

Description copied from interface: HelixGroupSelectionStrategy

Notify the corresponding Helix Group that the request is completed, and the implementation will decide whether any cleanup is required or not.

Specified by:

finishRequest in interface HelixGroupSelectionStrategy